"Today between 17.00 and 17.50 Moscow Standard Time (14.00-14.50 GMT) aircraft of the anti-IS coalition (two F-16 fighter jets and two A10s) delivered four air strikes near the airport of the city of Deir ez-Zor (Syria) on units of the Syrian governmental forces besieged by the Islamic State terrorist group (IS, outlawed in Russia)," Konashenkov said. "The coalition warplanes entered the airspace of the Syrian Arab Republic from Iraq."

The Syrian command in Deir ez-Zor said that 62 Syrian servicemen died in the air attack and about 100 more were wounded.

"Immediately after the anti-IS coalition’s air strike the IS militants launched an offensive," the defense ministry’s spokesman said.

"Now fierce armed clashes with terrorists are raging in the area of the airport, where humanitarian aid has been parachuted to local residents for a long time," Konashenkov said. "If this air strike was caused by a target location error, it is a direct consequence of U.S.’ stubborn unwillingness to coordinate with Russia its efforts against terrorist groups within Syria.".